jb wrote:Numbers up to ten are spelled out.
I actually found out from my english instructor that if the number's spelling equals two words (or less), it should be written out. I personally find that a little too lengthy in some cases, though. This rule is particularly for writing essays and such, not necessarily for business or statistical types of reports.
Here's my impression, for whatever it's worth. I've had a lot of caffeine and can't seem to keep myself from blathering on about this sort of thing.
In an essay you don't want your reader's brain to break out of essay-reading-mode into math-mode. If the fact of a 6 is important, rather than the fact that there are six, then use the numeral to get that across. Just as you would any set of options when writing. An object can be thrown, tossed, flung etc.
To be an artist is to make choices. Where we often fail is in the shallowness of our critical thinking. Everything's a choice. Let nothing be assumed. To put this concept in musical terms, 'cellists have a tendency to put vibrato on every note they possibly can, and the *same* vibrato on every note they possibly can. This is not the path to artistry, grasshopper! One should choose whether a note receives fast or slow vibrato, or none whatsoever. Good pop singers make that particular choice as a matter of course. Good writers should make similar choices.
Another 'cello example. Beginners use open strings. Advanced beginners, in a misconception of musicality, avoid them at all costs. Experts choose to use them or not, according to context.
In my regular life as a "technical" writer, I make such choices as a matter of craft rather than art. To be successful, the things I'm writing must lead the reader towards a specific result. So word choice is important. If I'm too clever, it's distracting. If I say 6 instead of six, it could be distracting, or be perceived as imprecise where precision (or the impression of precision) is required.
Blahblahblah turning head off now.